Airtight vehicle headlight having one-way valve

ABSTRACT

Headlight includes a reflector, having a removable bulb located at its focal point, sealed in airtight manner to a glass cover. Rear of bulb connected to a power source. A cap encloses the connection in airtight manner, the cap having a one-way valve permitting air to leave headlight but not to enter.

United States Patent Pierre Clble Paris, France 782,118

Dec. 9, 1968 July 12, 1971 Projecteurs Clble Boblgny, France Inventor Appl. No. Filed Patented Assignee AIRTIGHT VEHICLE HEADLIGHT HAVING ONE- WAY VALVE 2 Claims, 3 Drawing Figs.

U.S. Cl 240/41 R, 240/25, 240/41 SB, 240/4 1 .55

Int. Cl F2lm 3/00 Field of Search 240/41 R,

41.5,4l.55, 25, 3, 41 SB, 41.35

[56] References Cited UNITED STATES PATENTS 1,5 84,369 5/1926 Graham 240/41 2,347,055 4/1944 Johnson 240/41 3,325,637 6/1967 Soichiro Honda 240/4155 (X) FOREIGN PATENTS 1,324,249 3/1963 France 240/41 816,202 10/1951 Germany 240/41 S.B.U.

Primary Examiner -Samuel S. Matthews Assistant Examiner-Robert P. Greiner Attorney-Breitenfeld and Levine ABSTRACT: Headlight includes a reflector, having a removable bulb located at its focal point, sealed in airtight manner to a glass cover. Rear of bulb connected to a power source. A cap encloses the connection in airtight manner, the cap having a one-way valve permitting air to leave headlight but not to enter.

PATENIEU JUL 1 31971 illl! I HVEHTo'R: PI'I'I'I'Q humour vanrcus HEADLIGHT HAVING ONE-WAY I VALVE i The present invention relates to vehicle headlamps.

In the technology of vehicle headlamps, the expression optical unit refers to a unit comprising a reflector, a light source and a glass cover arranged in front of the reflector.

At the moment two basic types of optical units are known. The first is an optical unit with a detachable lamp which has been in use for a long time, mainly in Europe. An optical unit of this type is relatively cheap to manufacture and when its lamp is damaged it is easily replaced. However, it does have the major disadvantage of not being airtight, so that, on the one hand, dust or steam can settle on the reflector, the light source arid the rear side of the glass cover, which lessens the optical performance, and, on the other hand, the delicate reflecting layer of the reflector deteriorates quite rapidly under the effect of extreme influences. The second is an airtight and sealed optical unit of the type called sealed beam." An optical unit of type has been in use for quite a long time in the United States of America. It is provided with a lamp sealed once and for all to the reflector, and the light source can be constituted by at least one filament arranged inside the unit in an internal atmosphere similar to that of a lampjSuch sealed optical units have the advantage that the internal parts, and mainly the reflector, cannot be damaged and/or rusted by the ambient atmosphere, which means that the unit fully retains its optical properties aslong as it is in use. On the other hand,

sealed optical units are relatively expensive to manufacture due to the fact that it is very frequently necessary to establish a controlled atmosphere in the unit, while ensuring in all cases the airtightness ofthe assembly of these components. Further, in the case ofa failure of the light source, the entire unit must be replaced.

One object of the present invention is to provide an optical unit with a lamp which can be removed and replaced, and

which is not affected by the ambient atmosphere when it is in use.

Another object of the present invention is to provide an optical unit having a construction such that it can be assembled in a workshop at atmospheric pressure, the internal pressure of the unit being reduced when it is first used.

Another object of the present invention is to provide an optical unit combining the advantages of the sealed beam" optical unit and of the optical unit with a detachable lamp.

According to the invention, in order to achieve these various objects and advantages, there is proposed a new construction of optical unit in which a connection between the interior and the exterior of the unit is established by the intermediary ofa one-way valve or asimilar oneway component.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. I is an axial sectional view of an optical unit according to the invention;

FIG. 2 shows, in partial section, an embodiment of the cap used in the optical unit of FIG. 1; and,

FIG. 3 shows, in partial section, the cooperation of this cap with the supply wires of the lamp. I

The optical unit of FIG. 1 comprises, in known manner, a

reflector R of general parabolic shape, a lamp L at the focal plug 5 being bolted on to the annular flange l by means of lug 7 cooperating with an inwardly directed rim 8 of the flange l.

The construction described so far is known. According to the present invention, there is associated with the rear part of the optical unit in airtight manner a cap 10 having in its wall a one-way valve 11, which only permits passage of gas from the interior to the exterior of the cap 10, the supply wire 12 of the lamp L passing through the cap 10 in an airtight manner at 13.

Preferably, as shown, the cap 10 has a mounting aperture provided with an enlarged bead 10a. The airtight mounting of the cap 10 is thus obtained by locking of the bead 10a of the cap 10 between the edge 3 of the annular flange I and a radial projection 50 of the plug 5. Advantageously, in this case, the cap 10 is made ofa flexible plastics material, such as nylon or Rilsan.

The one-way valve 11 can be of any appropriate kind; it is only for a better understanding of the invention that it has been shown in FIG. 1 in the form ofa spring-loaded valve.

With the constructional components shown in FIG. 1, the operation of the optical unit according to the invention is easy to understand: It may be assembled in a workshop at at mospheric pressure. When it is used, that is when the lamp L is first illuminated, the optical unit becomes heated which increases the internal atmospheric pressure of the unit. Due to this pressure increase a large part of the air contained in the unit egresses through the one-way valve 11. When thelamp L is switched off there is no return of air. Even after a long .period of disuse, it the ambient atmosphere returns the inside of the unit to atmospheric pressure, the first subsequent illumination of the lamp L will produce an almost complete expulsion of this outer atmosphere.

In the modification of FlGS. 2 and 3, the one-way valve of the cap 10 is constituted by a lip valve 20, formed of an elastic plastics material, which tapers outwardly (FIG. 2). As can be seen in FIG, 3, the wire 12 from the lamp L passes through this lip valve 20in such a way that the airtightness of the one-way valve 20 is achieved by the gripping of the lip around the wire 12. Thus the one-way valve and the aperture for the wire are part of the same component, which greatly simplifies manufacture.

It is understood that the present invention is not limited to the embodiments described, but extends to all variations within the scope of the appended claims. In particular, the invention includes all variations in which the one-way valve, or its equivalent, is mounted directly on the glass cover or the reflector.

WhatIclaim is: v

I. A vehicle headlamp'optical unit comprising a. a reflector,

b. a glass cover attached in airtight manner to the front of said reflector,

a light source between said reflector and glass cover, said light source being capable when energized of emitting both light and heat, and

. means attached in airtight manner to the rear of said reflector making the optical unit as a whole airtight, said means including a one-way valve for permitting air to leave the interior of the optical unit but for preventing air from entering the unit,

whereby when said light source is energized it heats the air inside the optical unit and causes the air to leave through said one-way valve, the latter preventing reentry of air when said light source is deenergized and the optical unit cools.

2. A vehicle headlamp optical unit as defined in claim 1 including an electric wire connecting said light source to a power source, said wire entering the optical unit through said one-way valve. 

1. A vehicle headlamp optical unit comprising a. a reflector, b. a glass cover attached in airtight manner to the front of said reflector, c. a light source between said reflector and glass cover, said light source being capable when energized of emitting both light and heat, and d. means attached in airtight manner to the rear of said reflector making the optical unit as a whole airtight, said means including e. a one-way valve for permitting air To leave the interior of the optical unit but for preventing air from entering the unit, whereby when said light source is energized it heats the air inside the optical unit and causes the air to leave through said one-way valve, the latter preventing reentry of air when said light source is deenergized and the optical unit cools.
 2. A vehicle headlamp optical unit as defined in claim 1 including an electric wire connecting said light source to a power source, said wire entering the optical unit through said one-way valve. 